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Re^2: Split file into 4 smaller ones

by Anonymous Monk
on Feb 08, 2013 at 08:43 UTC ( #1017779=note: print w/replies, xml ) Need Help??


in reply to Re: Split file into 4 smaller ones
in thread Split file into 4 smaller ones

I always find it a bit silly when people suggest reading such large amounts of data into memory. Yes, I guess you can do that nowadays, but I'm not sure you always should. I prefer to conserve memory where possible.

use POSIX 'ceil'; my $buffer_size = 64 * 1024; my $bytes_wanted = ceil($size / 4); sub copy { my ($in, $out, $bytes) = @_; my ($buffer, $bytes_read); $bytes_read = sysread($in, $buffer, $bytes); print $out $buffer; return $bytes_read; } open my $in, '<', $infn or die $!; for my $outfn (1..4) { open my $out, '>', $prefix . $outfn or die $!; my $bytes = 0; while ($bytes + $buffer_size < $bytes_wanted) { $bytes += copy($in, $out, $buffer_size); } copy($in, $out, $bytes_wanted - $bytes); close $out; } close $in;

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[erix]: it might be cunning to mention the module in the title... :)
[ELISHEVA]: fancy that - a title that actually describes the problem :-)
[ELISHEVA]: but actually thanks for the reminder
[Discipulus]: DBI::CSV + utf8 = BOO?M
[erix]: in extremis we tend to forget stuff ;)
[ELISHEVA]: \Disciplus : lol
[Discipulus]: and ELISHEVA we waait one your post since ~2years... ;=)
[ELISHEVA]: has it really been that long?
[Discipulus]: it seems..
[Discipulus]: more: just one thread in the last ~5 years

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